what is the author's purpose of "Ain't I a women".

The prevailing theme of Truth's speech is equality—both between women and men, and between black and white. From the start, with her opening comparison between herself and woman's rights, she introduces the subject. She goes on to provide evidence for her assertion of equality, first by comparing her capacity for labor and strength with any man's, and then invoking biblical imagery and narratives to align her cause of equality with her Christian faith.